The WCTC-6 amphibious trailer, affectionately known as the "duckling," was made for use with the Landing Vehicle Tracked (LVT) and the amphibious truck. It had a 4.5-ton capacity with its 245-cubic-foot cargo box. Approximately 212 of these trailers were manufactured for the Army and USMC in 1944-1945. Women have held many roles in the U.S. military since its inception, including Agent 355, a woman spy employed by George Washington during the Revolutionary War whose true identity remains unknown, and Cathay Williams, the first black woman to enlist in the U.S. Army under the pseudonym William Cathay in 1866.